The Illustrated Book of Changes

( 易经图典 )

As far as its world outlook is concerned, The Book of Changes holds that all functions of the universe come from Nature. Hence, as an element of Nature, mankind should also follow such a spirit closely, without exception. As far as methodology is concerned, The Book of Changes is a logical system using Gougu Theorem (the Pythagorean Theorem) as its pivot, and uses time and space to unify all things in the universe in terms of their function (instead of their physical structure).